Get bedded in

One of the most critical of areas of a rifle is the barrel. But that’s not the be-all and end-all of rifle performance. You need to assess some other critical areas when weighing up a prospective buy. Of course, these issues do not just apply to checking a prospective buy, but also to keeping our existing rifles in good order. The first area to pay attention to is the bedding. Unless the rifle’s action is in intimate contact with the stock, it will not shoot accurately. Traditionally, this intimate contact was achieved through extremely skilled wood-working. In some cases, bedding areas were built up by gluing veneer into the critical area. Inevitably, gun oil would get into these areas, soften the wood and ruin the bedding.

Since the transition from SR(b) to Target Rifle, bedding has been achieved through the use of synthetic compounds in the critical areas. The bedding area is relieved to provide space for the compound; the action is coated with a release agent and then screwed into the stock; surplus compound oozes out and is trimmed off. When the chosen compound has gone off, the action can be removed from the bedding.

Photo 1.

Let’s look at what is important in a rifle built on a traditional Mauser or Mauser-derived action. Take a look a photo 1. At the front of the action is a flat portion underneath the receiver ring running up to where the bottom of the action is slotted for the magazine. Projecting below this is a rectangular recoil lug, which has a threaded hole for the front bedding screw. Little bearing area exists under the action rails flanking the magazine. This flat area must bear tight, as must the rear face of the recoil lug.

All that is relatively easy to achieve; but there’s a big caveat. The bottom of that recoil lug should not bear on the stock; neither should the bedding screw. The hole through which the screw passes should be large enough to ensure that the screw does not transmit any recoil to the stock – this is the recoil lug’s job.

Take a look at photo 2, which is a pretty typical early bedding job done on a converted Mauser. On the face of it, this looks good and has withstood around 40 years of use. There is some discoloration caused by rust (of which more later). There are no chips or cracks in the bedding. A gentle poke with a darning needle or scriber would reveal that the bedding has not gone spongy over the years. This bedding was probably done with a commercial epoxy based cable potting compound. The drawback is that the recoil lug is probably bottoming on the bedding. If this is the case, and the rifle shoots okay, it is probably best left alone. Converted military actions provide a bedding challenge because of the large aperture in the bottom of the action to accommodate the magazine. This results in little support to the rear of the receiver ring. If the rear tang is not bedded properly then the unsupported action can flex.

Photo 2.

These factors are eliminated in the case of a modern, solid-actioned, single-shot target rifle. This is clearly seen, for example, in the RPA Quadlock action shown in photo 3. Now look at photo 4. Compare the massive area of bedding against that of the Mauser. This is thanks to Devcon, a commercial mouldmaking compound.

Even if the bedding is in good shape, two factors can play havoc with its efficiency. The first is water getting into the bedding. No matter how good our wet-weather drill, water will get in. As soon as possible after a wet shoot, the rifle must be taken out of the stock and the action and bedding area thoroughly dried. Failure to do this in the case of the Mauser is evidenced by the heavy rust staining on the bedding surface. Even in the far more pristine action in photo 4, water has got into the bedding from time to time.

The other is oil. Gun oil always seems to creep into places where it’s not wanted. Again, you need to periodically remove the action from the bedding and ensure that the mating surfaces are oil-free.

Photo 3.

For the action to be in intimate contact with the bedding, the bedding screws (Americans call them action screws) need to clamp the action into the bedding. While there should not be a problem with synthetic or metal stocks, wood stocks can shrink. In addition, clamping the rifle into the bedding can compress the existing woodwork that lies under the bedding compound. More modern pillar bedding techniques mitigate this problem, but it is one you need to take heed of if you are likely to suffer from it. While it cannot be seen in the photo, the Barnard stock has a top hat-shaped aluminium bush glued into the underside of the stock. The woodwork has been substantially relieved around this bush to allow the bedding compound to produce a large, annular pillar around the screw hole.

The classic rifle shooter shooting a rifle where the action is bedded straight onto wood needs to be particularly vigilant. We need to ensure that the bedding screws are not bottoming and thus failing to clamp the action. In some rifles, the bedding screws are of similar length. When you remove them from the rifle, make sure you know which is which.

To check that the screws are not bottoming, first of all check that they are tight. Then carefully back the screw out of the action, counting the number of turns required to disengage the thread. Remove the action from the stock. This should be done with the stock in a vice or Workmate. Make sure you have protected the stock from damage. Lift the action out vertically. Avoid rocking the action, since this may damage the areas where the recoil lugs bear on the bedding. It often helps to insert the bolt, because you can get some vertical leverage on the underside of the open bolt.

Photo 4.

Once the rifle is out of the stock, gently insert the bedding screws. As soon as they engage the thread, count the number of turns before they bottom in the action. Since there is a measure of imprecision in this, there should be a reasonable margin between what you counted on the way out and what you counted on the way in.

If you have any doubt about the bedding screws bottoming, they should be dressed back. If this problem becomes persistent then something is being crushed (or the screw is being stretched) and remedial action will need to be taken. Good bedding is so fundamental to your rifle’s performance that you should not take chances with it. If you have any doubts, have the rifle re-bedded.

To ensure consistency in bedding tension and to avoid crushing woodwork or stretching screws, it is recommended that you use a torque wrench. A setting of 4.5 Newton metres is a good standard for target rifles. It is not necessarily a cheap piece of kit, but it is one that will repay the expenditure on the range. If you have one, you should use it periodically to ensure that your bedding screws are maintaining torque.